iwlwifi: additional parameter in REPLY_RX_PHY_CMD

Adding additional parameter in REPLY_RX_PHY_CMD, frame_time indicate the
frame's time on the air based on byte count and frame rate calculation

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-commands.h b/drivers/net/wireless/iwlwifi/iwl-commands.h
index 14a7a8c..13893a0 100644
--- a/drivers/net/wireless/iwlwifi/iwl-commands.h
+++ b/drivers/net/wireless/iwlwifi/iwl-commands.h
@@ -1401,7 +1401,7 @@
 	u8 non_cfg_phy_buf[32]; /* for various implementations of non_cfg_phy */
 	__le32 rate_n_flags;	/* RATE_MCS_* */
 	__le16 byte_count;	/* frame's byte-count */
-	__le16 reserved3;
+	__le16 frame_time;	/* frame's time on the air */
 } __packed;
 
 struct iwl_rx_mpdu_res_start {